A polymer refers to a compound having a large molecular weight, and to a compound formed by polymerizing several low molecular weight molecules called monomers. Polymers may be divided into linear polymers, branch polymers, cross-linked polymers, and the like according to a structure and a shape of a chain, and exhibit a significant difference in physical and chemical characteristics according to the structure.
Polymers have excellent mechanical strength and good processability in spite of the relatively light weight thereof, and have been usually used as a material constituting a structure, but the use thereof as a functional material has been recently highlighted due to excellent physical and chemical characteristics thereof.
Representative examples thereof include utilization for a polymer separation membrane. A polymer separation membrane means not a simple thin membrane such as a film, but a polymer membrane having a function of separating materials. Specifically, the polymer separation membrane has been used as an electrolyte membrane capable of exchanging positive ions, such as a fuel cell and a redox flow battery.
A fuel cell is an energy conversion device that converts the chemical energy of a fuel directly into electrical energy. That is, the fuel cell uses a fuel gas and an oxidizing agent, and adopts a method of producing electric power by using the electrons generated during the redox reaction of the fuel gas and the oxidizing agent. A membrane electrode assembly (MEA) of the fuel cell is a part in which an electrochemical reaction of hydrogen and oxygen occurs, and is composed of a cathode, an anode, and an electrolyte membrane, that is, an ion conductive electrolyte membrane.
A redox flow battery (oxidation-reduction flow battery) is an electrochemical storage device that stores chemical energy of an active material directly into electrical energy by using a system in which the active material included in an electrolytic solution is oxidized and reduced and thus charged and discharged. A unit cell of the redox flow battery includes an electrode, an electrolyte, and an ion exchange membrane (electrolyte membrane).
Fuel cells and redox flow batteries have been researched and developed as a next-generation energy source due to high energy efficiency and eco-friendly characteristics of less emission of contaminants.
One of the essential constituent elements of the fuel cells and the redox flow batteries is a polymer electrolyte membrane capable of exchanging positive ions, and in order to prepare a polymer membrane for a fuel cell and/or a redox flow battery having high durability and acid resistance, studies have been conducted on a monomer used during the synthesis of a polymer, a polymerization composition including the same, and the like.
[Patent Document] Official Gazette of Korean Patent Application Laid-Open No. 2003-0076057